174Hz 1+7+4=12; 1+2 = 3
285Hz 2+8+5=15; 1+5 = 6
396Hz 3+6+9=18; 1+8 = 9

417Hz 4+1+7=12; 1+2 = 3
528Hz 5+2+8=15; 1+5 = 6
639Hz 6+3+9=18; 1+8 = 9

741Hz 7+4+1=12; 1+2 = 3
852Hz 8+5+2=15; 1+5 = 6
963Hz 9+6+3=18; 1+8 = 9